Evaluation of Concrete Mixtures for Use in Underwater Repairs
Author: Billy D. Neeley
Publisher:
Published: 1988
Total Pages: 132
ISBN-13:
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Author: Billy D. Neeley
Publisher:
Published: 1988
Total Pages: 132
ISBN-13:
DOWNLOAD EBOOKAuthor: Billy Dale Neeley
Publisher:
Published: 1988
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKAuthor: Billy D. Neeley
Publisher:
Published: 1988
Total Pages: 134
ISBN-13:
DOWNLOAD EBOOKConcrete mixtures were evaluated to determine which were most suited for placement underwater in thin lifts. The concretes were proportioned to have good workability, good abrasion erosion resistance, and good resistance to washing out of the cement paste. High-range water reducers (HRWR) were used to increase the workability and permit the use of low water cement ratios (W/C) to increase the resistance to abrasion erosion. Low W/C, silica fume, and antiwashout admixtures (AWA) were used to increase the resistance to washout. A washout test was used to determine the relative amount of cement paste lost when the concrete is exposed to a large volume of water. The two-point workability test was used to evaluate the relative workability properties of each mixture. The slump and air content were also measured for most of the mixtures. The test method for abrasion erosion resistance of concrete (underwater method) was used to determine the abrasion erosion resistance of each mixture. The results of these tests were used to determine the combination of materials necessary to produce concrete with the desired properties. Significant correlations that exist between the two-point measurements and washout measurements were examined. The effects that W/C, HRWR's, AWA's, fly ash, and silica fume have upon washout resistance and abrasion-erosion resistance were examined.
Author: Billy D. Neeley
Publisher:
Published: 1990
Total Pages: 96
ISBN-13:
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Publisher:
Published: 1990
Total Pages: 90
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DOWNLOAD EBOOKConcrete mixtures were placed underwater using six placement techniques to (a) examine the cohesive and flow parameters of selected concrete mixtures under different placement situations, (b) estimate those parameters necessary for successful underwater placement, (c) examine the quality of bonding of the repair concrete to the existing concrete, and (d) examine the effect of underwater placement upon the abrasion resistance of the concrete. A washout test was used to determine the relative amount of cement paste lost when the concrete is exposed to a large volume of water. The two-point workability test was used to evaluate the relative workability properties of the concrete. The slump, tremie flow, and air content were also measured. The test method for abrasion-erosion resistance of concrete (underwater method) was used to determine the abrasion-erosion resistance of each concrete. A point-load test for tensile strength was used to determine the bond strength of the repair concrete to the existing concrete.
Author: KH. Khayat
Publisher:
Published: 1991
Total Pages: 10
ISBN-13:
DOWNLOAD EBOOKRepair of submerged concrete piles that have undergone considerable loss in cross section and strengthening of existing marine piles often involves jacketing the piles and filling the annular spacings between the jackets and the piles with concrete. In this paper, physical and mechanical properties that are deemed necessary to secure high-quality concrete under water were evaluated for numerous mixtures. Four concrete mixtures were selected to repair 2.4-m (8-ft)-high mock-up piles located above water. Rigid rectangular forms were erected around the 203-mm (8-in.)-square mock-up piles. The resulting annular spacings between these forms and the mock-up piles were first filled with water and then with concrete. The concrete was discharged within previously placed unhardened concrete to minimize segregation and water dilution rather than allowed to fall through water. Once the repair had set, the exposed surface of each underwater-cast pile was examined for any signs of segregation. Cores were obtained to evaluate the in-situ density and compressive strength of the concrete, as well as the bond strength between the underwater-cast concrete and the central mock-up pile. The testing program indicates that concrete mixtures containing antiwashout admixtures and either silica fume or fly ash can secure higher quality repairs, at equal or lower costs, than similar concretes made with high silica fume or high cement contents and no antiwashout admixtures. Properly proportioned concrete mixtures resulted in exposed repair surfaces free of segregation, with mean in-place compressive strength in excess of 58.6 MPa (8500 psi). The in-situ density of such concrete was identical to that cast and consolidated above water, and the bond strength to existing mock-up piles was in excess of 2.1 MPa (300 psi).
Author: William O. Tynes
Publisher:
Published: 1976
Total Pages: 36
ISBN-13:
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Publisher:
Published: 1989
Total Pages: 390
ISBN-13:
DOWNLOAD EBOOKAuthor: American Concrete Institute
Publisher: American Concrete Institute
Published: 2005
Total Pages: 660
ISBN-13: 0870311948
DOWNLOAD EBOOKAuthor: Edward G. Nawy
Publisher: CRC Press
Published: 2008-06-24
Total Pages: 1586
ISBN-13: 1420007653
DOWNLOAD EBOOKThe Concrete Construction Engineering Handbook, Second Edition provides in depth coverage of concrete construction engineering and technology. It features state-of-the-art discussions on what design engineers and constructors need to know about concrete, focusing on - The latest advances in engineered concrete materials Reinforced concrete construction Specialized construction techniques Design recommendations for high performance With the newly revised edition of this essential handbook, designers, constructors, educators, and field personnel will learn how to produce the best and most durably engineered constructed facilities.